Clamping mechanism



CLAMPING MECHANISM Filed March 14, 1932 Patented Feb. 6, 1934 UNITED STATES CLAIVIPING MECHANISM William J. Lowe, Chicago, Ill., assignor to Sarah B. Welker, doing business as Welker Die & Machine Works, Chicago, 111.

Application March 14, 1932. Serial No. 598,653

4 Claims.

The device is particularly adapted for use in holding the freshly glued ends of articles, such as, for example, lamp shades, for a suflicient period to permit the glue to set. The operation is one in which freshly glued articles are placed in and removed from clamping jaws successively. The device is arranged in a manner whereby all the clamping jaws hold a glued article except at one point in its cycle of movement where each jaw is successively released from the finished article permitting a freshly glued piece to be put in place between the jaws.

It is a particular object of this invention to provide a single treadle means for moving one of a series of clamping bars into engaging position so that the operators hands are free to manipulate the article being clamped.

As an exemplification of my invention, reference is made to the accompanying drawing, in 'which Figure 1 is a view of the clamping device in sectional elevation showing two of the diagonally opposite clamping devices, one in released position, and the other in clamped position;

Fig. 2 is an enlarged fragmentary view of the lower portion of the device, and taken as indicated by the line 22 of Fig. 1;

Fig. 3 is a plan sectional view of the upper flange plate taken on the line 3 of Fig. 1;

Fig. 4 is an enlarged sectional view of the slip joint taken on the line 4 of Fig.1;

Fig. 5 is an enlarged elevation of the clamping bars showing the ends of an article clamped therebetween; and

Fig. 6 is an enlarged fragmentary perspective view of a modified form of treadle and actuating means for the rotating shaft, the treadle being shown in elevated position.

The embodiment illustrated comprises a base 10 upon which is rotatably mounted a vertical shaft 11, the shaft being held against axial movement in the base by a screw 12. Secured to the shaft is an upper flange plate 13 and a lower flange plate 14, the plates being provided with 5 aligned openings 15 and 16 respectively, in which are slidably fitted push rods 17.

The upper flange plate is provided with a series of clamping devices extending radially from the shaft. Each clamping device comprises an arm 18, rigidly secured to the flange plate as by screws 19, and a co-operating clamp bar 20 adapted to be moved toward and away from the arm. The mechanism for moving the clamp bar may be a lever 22 pivotally connected at one end to the clamp bar and at its other end to one of the push rods. Each lever is'rockable on a post 23 which serves as a fulcrum for a leverof the first class.- It will be seen that as the push rods are moved upward the levers are rocked to move the clamp bars toward the arms, thereby exerting a clamping pressure upon any work that is rested upon the bar 20, as, for example, a lamp shade 24. r

The mechanism for actuating the push rods may comprise a treadle 25 pivoted at26 to a rigid arm 27 extending outwardly from the base. The treadle terminates in a foot 28 which lies directly beneath the ends of the push rods in succession. A cam surface 29 is formed on the base at a suitable height and made circular to conform to the circular path traveled by the push rod ends. The cam is provided with a depressed portion 30 and a cut-out portion 31 in which rests the foot of the treadle. v 7

Each push rod is provided with a roller 33 at its lower end adapted to ride on the cam surface, and held thereagainst by a coilspring 34 whose opposite ends are thrust against the flange plate 14 and a collar 35 secured on the rod. Each rod is furthermore extensible as by slidably connecting two tubular rod sections, as shown in Fig. 4, the purpose of which is to allow for variations in the thickness of material placed between the clamping jaws. The slip joint may utilize a guide pin 36 secured to one rod section'and fitting slidably into the other, with a spring 37 interposed between the two sections to normally maintain the rod section extended from each other. The guide may be locked in place with a transverse pin 38 extending outwardly through a slot 39 and movable therein to permit a limited movement of one rod section relative to the other.

The clamping device is operated in the following manner: The operator stands in a position adjacent the treadle where two of the clamping jaws are held open by the spring 34 which move the associated push rods into the depression 30 in the cam. It will be noted, by referring to Fig. 2, that one of the push rods rests in the depression 30 and. the other rests on the foot of the treadle. The operator places an article the next push rod into position over the foot of the treadle and to permit another push rod to be lowered in the depression 30. It will be seen that each clamping jaw continues to maintain pressure on the work until the entire clamping device has made substantially one revolution. The time required to complete this cycle of movement is sufiicient to permit glue to set, thereby adapting the mechanism to such uses as the manufacture of lamp shades, etc.

In the modified form shown in Fig. 6, the

arrangement of parts is the same as already described except that a sprocket Wheel 41 is secured to the shaft 11, the spokes being extended over the foot of the treadle to which is secured an upstanding cam 42. As the treadle is operated to raise the push rod, the cam engages one of the spokes thereby turning the shaft slightly so that the push rod end is moved upon the cam 29. After the foot of the treadle has been returned to lowered position the shaft is rotated by hand, as previously described, so that the next succeeding push rod is moved to a position where it rests upon the foot.

I claim:

1. A turret clamping device comprising a base, a shaft rotatable on the base, push rods mounted to rotate with the shaft and adapted to move axially,'clamping devices extending radially of the shaft and actuated by the push rods, a treadle on the base adapted to move the push rods one at a time to actuate the clamping devices, means for retaining the clamping devices in clamping position While the shaft is rotated, and means on the treadle for imparting initial rotary movement only to the shaft.

2. A turret clamping device having a rotatable shaft, a plurality of clamping means mounted to rotate with the shaft, operating means for the clamping means comprising push rods mounted to rotate with the shaft and shiftable longitudinally, a stationary circular cam having an opening therein adjacent one end of the push rods adapted to hold the rods in a position whereby the clamping means are operated while being rotated, a spring for forcing the push rods into the cam opening to release the clamping means, and a treadle located in the opening in the cam for successively moving the push rods to operate the clamping means.

3. A turret clamp mechanism in which is combined, a plurality of movable clamps mounted to travel through a definite path, operating rods for the clamps also mounted to travel through the same path, a cam extended through the same path in operative relation to the rods I, adapted to'operate the latter and thereby the clamps, and manually controlled means in cooperation with the cam effective at 'one point in the movement cycle of the mechanism to operate the rods successively independent of the cam.

4. A turret clamping mechanism in which is combined a base, a cam thereon having a depression in its surface, a shaft rotatable upon the base, clamping devices extending radially from the shaft and rotatable therewith, operating rods each having one end in contact with the cam surface and its other end connected to one of the clamping devices for operating the same, and means engageable successively with the operating rods for moving each rod in turn from the depression to the plane of the cam surface.

WILLIAM 'J. LOWE 

